This week I competed in the Three Minute Thesis (3MT)! It’s an international research competition where graduate students have three minutes to present their research and its impact to an intelligent but non-specialist audience.  The first 3MT competition was held at the University of Queensland in Australia in 2008.  It’s now a multi-national competition, including an annual provincial competition in Ontario. The exercise helps students develop communication skills essential to making their research impactful.

I really enjoyed the opportunity to participate and to hear the other graduate students’ 3MTs.  There was a great feeling of support and encouragement among the competitors and I learned a lot about the amazing research going on at my university.  I would highly recommend the experience to anyone in graduate school!

If you’re interested in my presentation, you can see the transcript below.

Most people know that our world is made up of matter, but why couldn’t the world be made of antimatter instead?  Would the laws of physics change?  Would we fall UP due to antigravity?  It may seem like the stuff of science fiction, but you have more experience with antimatter than you think.

It might surprise you to know that YOU are emitting antimatter; about once every 75 minutes!  Potassium-40, found in bananas (and also in humans), is a radioactive isotope that emits positrons when it decays, the antimatter counterpart of an electron.  We also use antimatter for medical imaging in PET scanners, where the “P” stands for positron.  Antimatter seems exotic because there isn’t much of it around, but antimatter is just the mirror image of regular matter.  In theory, all of their properties and interactions are the same, the only difference is that the properties described by quantum mechanics are opposite in sign.  When matter and antimatter meet, they annihilate and create energy as per Einstein’s famous equation, E=mc^2.

The Standard Model of physics predicts that both matter and antimatter should have been created in equal amounts during the Big Bang.  But if that were the case they would have annihilated entirely and the universe today would just be leftover energy.  Why did so much matter survive, or, what happened to all of the antimatter?  The imbalance is know as the Asymmetry Problem, and it remains one of the biggest questions in modern physics.

I work with the ALPHA collaboration at CERN, and we are looking for differences between matter and antimatter by comparing their properties to extremely high precision.  Any differences we observe would be direct evidence of new physics that might explain the asymmetry problem.  So far physicists have measured and compared antimatter’s mass, charge, and magnetic moment, and they all agree with the same quantities for matter.  Most recently, our collaboration used lasers to study how antihydrogen interacts with light, and again the spectrum agreed with that of hydrogen.

Our next comparison requires measuring antigravity to see if antimatter interacts the same way that matter does with the gravitational force.   I am helping to build a new experiment called ALPHA-g that will begin taking data in 2018.  We will trap antihydrogen atoms, and when we let them go, measure how far they fell in the time before they annihilated with the walls of the trap.  We detect these annihilations and use them to calculate the acceleration due to “antigravity.”

With each successful comparison of matter to antimatter we further confirm that our current models are correct, but the most interesting result would be a disagreement that would give the physics community a window into interesting new physics, and potentially a deeper understanding of why we live in a matter dominated universe.

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